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ffmpeg
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store searched distance in index, so we dont waste time searching for keyframes where we already searched 

asf seek fixes & use keyframe pos/timestamp cache

Originally committed as revision 2709 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-01-17 18:06:52 +00:00
parent fb204d4bc1
commit 3e9245a98e
4 changed files with 88 additions and 26 deletions
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90
libavformat/asf.c
View File

@ -1355,11 +1355,17 @@ static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
ASFStream *asf_st;
int64_t pts;
int64_t pos= *ppos;
int i;
int64_t start_pos[s->nb_streams];
for(i=0; i<s->nb_streams; i++){
start_pos[i]= pos;
}
//printf("asf_read_pts\n");
url_fseek(&s->pb, pos*asf->packet_size + s->data_offset, SEEK_SET);
asf_reset_header(s);
do{
for(;;){
if (av_read_frame(s, pkt) < 0){
printf("seek failed\n");
return AV_NOPTS_VALUE;
@ -1367,11 +1373,23 @@ static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
pts= pkt->pts;
av_free_packet(pkt);
}while(pkt->stream_index != stream_index || !(pkt->flags&PKT_FLAG_KEY));
asf_st= s->streams[stream_index]->priv_data;
if(pkt->flags&PKT_FLAG_KEY){
i= pkt->stream_index;
assert((asf_st->packet_pos - s->data_offset) % asf->packet_size == 0);
*ppos= (asf_st->packet_pos - s->data_offset) / asf->packet_size;
asf_st= s->streams[i]->priv_data;
assert((asf_st->packet_pos - s->data_offset) % asf->packet_size == 0);
pos= (asf_st->packet_pos - s->data_offset) / asf->packet_size;
av_add_index_entry(s->streams[i], pos, pts, pos - start_pos[i] + 1, AVINDEX_KEYFRAME);
start_pos[i]= pos + 1;
if(pkt->stream_index == stream_index)
break;
}
}
*ppos= pos;
//printf("found keyframe at %Ld stream %d stamp:%Ld\n", *ppos, stream_index, pts);
return pts;
@ -1380,33 +1398,70 @@ static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
{
ASFContext *asf = s->priv_data;
AVStream *st;
int64_t pos;
int64_t pos_min, pos_max, pts_min, pts_max, cur_pts, pos_limit;
if (stream_index == -1)
stream_index= av_find_default_stream_index(s);
if (asf->packet_size <= 0)
return -1;
pos_min = 0;
pts_min = asf_read_pts(s, &pos_min, stream_index);
if (pts_min == AV_NOPTS_VALUE) return -1;
pos_max = (url_filesize(url_fileno(&s->pb)) - 1 - s->data_offset) / asf->packet_size; //FIXME wrong
pts_max = pts_min + s->duration;
pos_limit= pos_max;
pts_max=
pts_min= AV_NOPTS_VALUE;
pos_max= pos_limit= -1; // gcc thinks its uninitalized
st= s->streams[stream_index];
if(st->index_entries){
AVIndexEntry *e;
int index;
index= av_index_search_timestamp(st, pts);
e= &st->index_entries[index];
if(e->timestamp <= pts){
pos_min= e->pos;
pts_min= e->timestamp;
#ifdef DEBUG_SEEK
printf("unsing cached pos_min=0x%llx dts_min=%0.3f\n",
pos_min,pts_min / 90000.0);
#endif
}else{
assert(index==0);
}
index++;
if(index < st->nb_index_entries){
e= &st->index_entries[index];
assert(e->timestamp >= pts);
pos_max= e->pos;
pts_max= e->timestamp;
pos_limit= pos_max - e->min_distance;
#ifdef DEBUG_SEEK
printf("unsing cached pos_max=0x%llx dts_max=%0.3f\n",
pos_max,pts_max / 90000.0);
#endif
}
}
if(pts_min == AV_NOPTS_VALUE){
pos_min = 0;
pts_min = asf_read_pts(s, &pos_min, stream_index);
if (pts_min == AV_NOPTS_VALUE) return -1;
}
if(pts_max == AV_NOPTS_VALUE){
pos_max = (url_filesize(url_fileno(&s->pb)) - 1 - s->data_offset) / asf->packet_size; //FIXME wrong
pts_max = s->duration; //FIXME wrong
pos_limit= pos_max;
}
while (pos_min < pos_limit) {
int64_t start_pos;
assert(pos_limit <= pos_max);
// interpolate position (better than dichotomy)
pos = (int64_t)((double)(pos_limit - pos_min) *
(double)(pts - pts_min) /
(double)(pts_max - pts_min)) + pos_min;
pos/= asf->packet_size;
if(pos <= pos_min)
pos= pos_min + 1;
else if(pos > pos_limit)
@ -1415,8 +1470,11 @@ static int asf_read_seek(AVFormatContext *s, int stream_index, int64_t pts)
// read the next timestamp
cur_pts = asf_read_pts(s, &pos, stream_index);
#ifdef DEBUG_SEEK
printf("%Ld %Ld %Ld / %Ld %Ld %Ld target:%Ld limit:%Ld start:%Ld\n", pos_min, pos, pos_max, pts_min, cur_pts, pts_max, pts, pos_limit, start_pos);
#endif
if (cur_pts == AV_NOPTS_VALUE) {
printf("NOPTS\n");
return -1;
} else if (pts < cur_pts) {
pos_limit = start_pos - 1;

7
libavformat/avformat.h
View File

@ -196,9 +196,8 @@ typedef struct AVIndexEntry {
int64_t timestamp;
#define AVINDEX_KEYFRAME 0x0001
/* the following 2 flags indicate that the next/prev keyframe is known, and scaning for it isnt needed */
#define AVINDEX_NEXT_KNOWN 0x0002
#define AVINDEX_PREV_KNOWN 0x0004
int flags;
int min_distance; /* min distance between this and the previous keyframe, used to avoid unneeded searching */
} AVIndexEntry;
typedef struct AVStream {
@ -549,8 +548,8 @@ void av_set_pts_info(AVFormatContext *s, int pts_wrap_bits,
int av_find_default_stream_index(AVFormatContext *s);
int av_index_search_timestamp(AVStream *st, int timestamp);
void av_add_index_entry(AVStream *st,
int64_t pos, int64_t timestamp, int flags);
int av_add_index_entry(AVStream *st,
int64_t pos, int64_t timestamp, int distance, int flags);
/* media file output */
int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap);

2
libavformat/mpeg.c
View File

@ -909,7 +909,7 @@ static int mpegps_read_pes_header(AVFormatContext *s,
int i;
for(i=0; i<s->nb_streams; i++){
if(startcode == s->streams[i]->id) {
av_add_index_entry(s->streams[i], *ppos, dts, 0 /* FIXME keyframe? */);
av_add_index_entry(s->streams[i], *ppos, dts, 0, 0 /* FIXME keyframe? */);
}
}
}

15
libavformat/utils.c
View File

@ -861,8 +861,8 @@ static void av_read_frame_flush(AVFormatContext *s)
}
/* add a index entry into a sorted list updateing if it is already there */
void av_add_index_entry(AVStream *st,
int64_t pos, int64_t timestamp, int flags)
int av_add_index_entry(AVStream *st,
int64_t pos, int64_t timestamp, int distance, int flags)
{
AVIndexEntry *entries, *ie;
int index;
@ -890,12 +890,17 @@ void av_add_index_entry(AVStream *st,
}
st->nb_index_entries++;
}
}else
ie= &entries[st->nb_index_entries++];
}else{
index= st->nb_index_entries++;
ie= &entries[index];
}
ie->pos = pos;
ie->timestamp = timestamp;
ie->min_distance= distance;
ie->flags = flags;
return index;
}
/* build an index for raw streams using a parser */
@ -916,7 +921,7 @@ static void av_build_index_raw(AVFormatContext *s)
if (pkt->stream_index == 0 && st->parser &&
(pkt->flags & PKT_FLAG_KEY)) {
av_add_index_entry(st, st->parser->frame_offset, pkt->dts,
AVINDEX_KEYFRAME);
0, AVINDEX_KEYFRAME);
}
av_free_packet(pkt);
}